Drug Evaluation Oncologic, Endocrine & Metabolic: Bicalutamide (Casodex™)

Abstract

Bicalutamide (Casodex™) is a relatively new non-steroidal antiandrogen indicated for use in combination therapy with castration for the treatment of advanced prostate cancer. Developed from a series of non-steroidal compounds related to flutamide, bicalutamide is a potent, orally active, well tolerated anti-androgen with a half-life compatible with once-daily administration. In the clinical programme in prostatic cancer, patients were exposed to bicalutamide in doses ranging from 10 - 600 mg. Doses of 10 - 200 mg have been shown to have intrinsic activity in terms of producing subjective improvement and objective responses, and daily doses of up to 600 mg are currently being evaluated. Results of monotherapy studies reveal that 50 mg of bicalutamide is less effective than castration in patients with advanced disease; Phase III monotherapy studies are ongoing to compare 150 mg of bicalutamide with castration. In monotherapy studies, both 50 mg and 150 mg of bicalutamide have an advantage over castration in allowing patients to maintain libido and sexual potency. As combination therapy, 50 mg bicalutamide and a luteinising hormone-releasing hormone (LHRH) analogue is at least as effective as 750 mg of flutamide and an LHRH analogue and is better tolerated. The overall safety and tolerability profile of bicalutamide is indicative of a well tolerated therapy that has a relatively low incidence of treatment-related withdrawals. Because of its efficacy in combination with medical castration, its excellent safety profile, and its convenient once-daily oral formulation, bicalutamide represents a valid choice for anti-androgen therapy when used in combination with castration for patients with advanced prostate cancer.